Bleeding and blood loss are problems that must be addressed during and at the conclusion of surgery and other medical procedures. Significant blood loss can be fatal or cause significant morbidity, and surgeons and medical staff routinely compensate for blood loss with transfusions and the use of recirculating devices. A number of different techniques and products are currently used by surgeons to stop bleeding and effect hemostasis in surgery and medical procedures. However no single approach is effective or suitable under all circumstances, and the currently available approaches have limitations in effectiveness, safety, applicability and ease of use.
The most commonly used approaches involve closing a tissue or blood vessel mechanically with a suture or staple. This ligature technique is often effective, though it may allow for minor bleeding to occur around suture or staple holes. Sometimes biological or synthetic adhesives are applied to either complement or replace sutures or staples to stop this blood flow. However, tissue sealants are not hemostats per se and allow the pooling of blood underneath the seal in cases of moderate bleeding that may result in the formation of a hematoma. Hemostatic products which require time-consuming application or which produce slow effective action can be costly both in terms of financial costs due to greater operating room time and in terms of post procedure patient morbidity. Some techniques and products have limited effectiveness in certain applications, which may require a surgeon to reapply the product or switch to another product, which can be both time consuming and costly.
Under certain circumstances standard ligature techniques are inappropriate or not feasible. In such cases, an absorbable hemostatic product can be applied to the bleeding surface with a goal of achieving hemostasis that will later lead to a durable clot formation. Passive hemostats can control bleeding through absorption and may be powders, gauze, sponges or cross-linked gelatin. Sometimes these are augmented with an active hemostatic agent such as thrombin to try to achieve a successful hemostasis. However, the efficacy of these products is often variable and their use has been associated with adverse effects which can provide significant challenges during a surgical procedure. Such challenges become especially pronounced in certain surgical procedures such as brain and spinal surgeries. For example, certain sponges derived from porcine material can absorb up to 45-times their weight in blood and fluids resulting in significant swelling of the product that can lead to a patient experiencing adverse reactions such as pain, paresis or paralysis that can require revision surgery to address. Certain particulate hemostats have been reported to have caused cerebral edema. Gelatin-based devices typically swell during use and have been reported to cause mass effects leading to the development and progression of hemiparesis that required revision surgery to address the situation. Other adverse events and complications have been reported for all these types of hemostats. Most of these devices rely on absorption of blood and body fluids to produce hemostasis, which results in swelling and can lead to the reported mass effects.
The slow action of available absorbable hemostats, which are often used multiple times per case, can add to the length of surgical procedures, adding to expense and post-operative morbidity. Certain commercially available hemostats require as much as 10 minutes to produce hemostasis for each incidence of bleeding during a surgical procedure.
Accordingly, there remains a need for a fast acting, ready to use, biocompatible, biodegradable hemostat that minimizes or prevents bleeding and blood loss, does not swell during use and promotes stable clot formation during a wide variety of surgical procedures including cranial and spinal surgeries and in minimally invasive surgical procedures, and significantly reduces the incidence of postoperative adverse events.